### University of Crete HEP Seminars

**
Higher form symmetries and superfluids
**

Speaker: | Diego Hofman |

Institution: | University of Amsterdam |

Time: | Monday 23 September 2019, 14:15 |

Venue: | 2nd floor seminar room |

Abstract: | I will describe superfluid hydrodynamics as the hydrodynamic theory of a system with an emergent anomalous higher-form symmetry. The higher-form charge counts the winding planes of the superfluid -- its constitutive relation replaces the Josephson relation of conventional superfluid hydrodynamics. This formulation puts all hydrodynamic equations on equal footing. The anomalous Ward identity can be used as an alternative starting point to prove the existence of a Goldstone boson, without reference to spontaneous symmetry breaking. This provides an alternative characterization of Landau phase transitions in terms of higher-form symmetries and their anomalies instead of how the symmetries are realized. This treatment is more general and, in particular, includes the case of BKT transitions. |

**
Dark matter search and gravitational wave detection using atom interferometry
**

Speaker: | Wolf von Klitzing |

Institution: | IESL-FORTH Crete |

Time: | Thursday 26 September 2019, 14:15 |

Venue: | 2nd floor seminar room |

Abstract: | In a recent White Paper (arXiv:1908.00802) we proposed a concept for a space experiment using cold atoms to search for ultra-light dark matter, and to detect gravitational waves in the frequency range between the most sensitive ranges of LISA and the terrestrial LIGO/Virgo/KAGRA/INDIGO experiments. This interdisciplinary experiment, called Atomic Experiment for Dark Matter and Gravity Exploration (AEDGE), will also complement other planned searches for dark matter, and exploit synergies with other gravitational wave detectors. We give examples of the extended range of sensitivity to ultra- light dark matter offered by AEDGE, and how its gravitational-wave measurements could explore the assembly of super-massive black holes, first-order phase transitions in the early universe and cosmic strings. AEDGE will be based upon technologies now being developed for terrestrial experiments using cold atoms (also on Crete), and will benefit from the space experience obtained with, e.g., LISA and cold atom experiments in microgravity. |

**
The Geometric Trinity of Gravity: the TEGR case
**

Speaker: | Konstantinos Dialektopoulos |

Institution: | Center for Gravitation and Cosmology, Yangzhou University |

Time: | Friday 27 September 2019, 16:15 |

Venue: | 2nd floor seminar room |

Abstract: | It is well established by now that General Relativity and the LCDM model are very successful in describing the gravitational interactions at all scales. However, the theory is plagued with some shortcomings, enabling scientists to pursue an alternative formulation of gravity. In this talk, I am going to review the three different formulations of gravity; one based on the curvature of spacetime (General Relativity), one based on its torsion (Teleparallel Equivalent of General Relativity, TEGR) and one based on its non-metricity (Symmetric Teleparallel of General Relativity, STEGR). I will try to focus on the TEGR, explaining some of its key features. |

**
Fine Tuning Problems from Cosmological Coleman-Weinberg Potentials
**

Speaker: | Richard Woodard and S.P. Miao |

Institution: | University of Florida |

Time: | Monday 21 October 2019, 14:15 |

Venue: | 2nd floor seminar room |

Abstract: | TBA |